Electric switch



J. D. HILLIARD ELECTRIC SWITCH Filed Jan. 2, 1924 2 Sheets-Sheet l 5 552 gig; 2%

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O J Uu b Patented a. 22, 1929 UNITED STATES PATENT OFFICE JOHN D.HILLIARD, 0F SCHENECTADY, NEW YORK, ASSIGNOR TQ GENERAL ELEC'DBIQCOMPANY, A CORPORATION OF NEW YORK ELECTRIC SWITCH Application filedJanuary 2, 1924. Serial No. 684,004.

My invention relates to electric switches of the fluid break type and anobject of my invention is to provide an improved construction of switchof this type, the construction being such that the switch is adapted tobe mounted on a pole for'usc as a line disconnecting switch.

Heretotore the connection between branch transmission lines and the mainline has customarily been eil'ected by means of a simple air breakswitch. WVhere the operating voltage is high and the branch line to beisolated is of considerable length, the charging current of the branchis of such a magnitude that it is not adapted to be broken by thedisconnecting switches now in common use. In accordance with myinvention, I have provided for this purpose a fluid break switch of theexplosion chamber type, each chamber having an upwardly extending tubeof insulating material secured to it, through which extends a rodcontact member when the circuit is closed and from which the rod isrelatively withdrawn when the circuit is open. To maintain the liquid inthe chamber and tube at the desired level I have provided a reservoirenclosing those parts and in communication with the chamber through asmall opening therein.

My invention will be better understood by reference to the accompanyingspecification and drawing and its scope will be pointed out in theappended claims.

Figure 1 is a verticalsectional view of one form of switch embodying myinvention, and Fig 2 is a similar view of another form of my invention.

Referring first to Fig. 1, a cross arm or other suitable support 1carries two spaced insulators 2 and 3 upon which are mounted thestationary elements of two fluid break switch structures. As these twostructures are identical in every respect, the one supported byinsulator 2, only, will be described in detail. A cup-shaped terminal 4to which a lead 5 may be attached for connection to an electric circuitclamps around the depending portion 6 of a base plate 7. A contactholder 8 is shown threaded into the portion 6 and surrounded by thisholder and connected thereto is the stationary socket contact 9 which asillustrated may be of the segmental type. An explosion or pressurechamber enclosing the contact 9 is formed in part by the strong metalcasing 10 and the holder 8. The casing 10 may be secured as shown byscrew threading it to the holder 8 whereby it may be readily removed topermit inspection or removal. of the contacts 9. In the top wall of thecasing 10 a tube 12 of insulating material, for example a phenoliccondensation product such as bakelite, is secured and surrounding thecasing 10 and the greater portion of the tube 12 is a vessel 13 whichwith the base plate 7 forms a reservoir for the are extinguishing fluid.This vessel 13 which may for example be constructed of stone ware, fitssnugly around the tube 12 and is shown secured to the base plate 7 bycementing it to the ring 14. bolted to the base plate. The casing 10 isprovided, preferably at its upper wall, with a small opening or bleedhole 15 for allowing the are extinguishing liquid to refill the chamberafter each opening of the switch. The top of the reservoir or vessel 13is also provided with a small opening 16 to connect the interior of thevessel with the outside atmosphere.

The movable contact member of the switch shown in Fig. 1 comprises a rod20 which is secured at its upper end to a bridge 21. The tube 12 throughwhich the rod 20 extends is preferably though not necessarily materiallylarger than the rod. At each end, the bridge 21 carries a shield 22having an outer flange 23 and an inner flange 24. The inner flange dipsinto a trough 25 in the annular member 26, filled for example with oilto provide a liquid seal to prevent evaporation of the liquid in thetube 12 when a volatile liquid is used. The arrangement also preventsthe entrance of rain. Secured to the underside of the bridge 21 are twocontact members 27 and 27 which when the switch is in closed positionengage respectively contact memhers 28 and 29 carried by the base plates7 as shown, thus providing the main current carrying means of theswitch. For raising and lowering the bridge 21 as in opening and closingthe switch, a rod 30 which may be in part or wholly of wood is providedwhich has sliding engagement with the bridge 21 and with an insulator30' mounted in the sup port 1. This rod is preferably square in crosssection to prevent turning of the bridge 21 and has secured to it twoflanges 31 and 32 and a cross arm 33. A compression spring 34 is shownbetween the flange 31 and the bridge 21 and a pair of tension springs 35connect the bridge 21 to the cross arm 33. To open the switch theoperator who may be standing on the ground beneath the switch pushesupwardly on the rod 30 stressing the springs 34:

and 35 which causes a sudden separation of the switch contacts. Thecontact rods 20 are preferably completely withdrawn from the tubes 12,leaving an air gap between the ends of the rods 20 and the insulatingliquid.

1n the form of my invention illustrated by Fig. 2 the contact rods 20are held in fixed position and the socket contacts 9 and associatedparts are adapted to be moved up and down respectively to close and openthe switch. In this case, each contact rod 20 is secured to a support 38carried by an insulator 39 on a cross arm and adapted to be connected bya conductor 40 to the line. The construction of the socket contact andthe parts connected and related thereto are similar to those describedabove in connection with Fig. 1 with the exception that in this case theswitch comprising contacts 27, 27, 28 and 29 are omitted and theterminals 4.- are permanently connected together by a bar 11. Theinsulators 2 and 3 are shown bolted to across bar 42 which may be ofwood and attached to this bar is shown an operating rod 43 whichpreferably is square and passes through a square opening in the bar orarm 44. To open the switch according to this form of the invention therod 43 is lowered until the rod and the socket contacts are separatedand the tubes 12 are entirely withdrawn from the contact rods. In thisposition the socket contacts may be inspected or renewed, the reservoirsmay be filled and any other needed attention given to the partsconnected therewith without danger from the line and without the use ofadditional disconnecting switches.

The are extinguishing liquid is shown in both forms of the invention asnearly filling the reservoirs and may consist of oil, water, a mixtureof water and glycerine or any other liquid having a fairly highdielectric strength. Inasmuch as complete separation is provided forbetween the contact rod and the liquid, an extremely high insulatlngproperty of the liquid used is not such an important consideration as itis in switches where the contact rod remains in the liquid. Vhen ahydrous liquid is used evaporation of the liquid may obviously befurther reduced by applying a film of oil thereto.

While I have described only one embodiment of my invention, I do notwish to be limited to the particular form shown and described as it willbe apparent that many modifications therein may be made withoutdeparting from the scope of my invention as set forth in the appendedclaims.

\Vhat I claim as new and desire to secure by Letters Patent of theUnited States, is,-

1. An electric switch of the fluid break type comprising a pressurechamber, a fixed contact therein, a vessel adapted to contain a supplyof insulating liquid, said chamber having a small passage through whichthe insulating liquid may enter the chamber from the vessel, a dischargetube connected with the top of the pressure chamber and extendingupwardly therefrom and a movable contact cooperating with said fixedcontact and arranged to be initially separated therefrom in the pressurechamber and to be withdrawn from the discharge tube.

2. An electric switch of the fluid break type comprising a pressurechamber, a fixed contact therein, a vessel adapted to contain a sup plyof insulating liquid for the chamber, said chamber having a smallpassage through which the insulating liquid may enter from the vessel,an insulating discharge tube connected with the pressure chamber andextending therefrom up through the vessel, a contact rod extendingthrough the discharge tube and spaced from the walls thereof and meansfor withdrawing the rod from the fixed contact and from the tube.

3. An electric switch of the fluid break type comprising a pressurechamber closed at its lower end and containing a fixed contact, adischarge tube extending up from the cham her, a movable contactarranged to be with drawn from the'fixed contact through the dischargetube and a reservoir for insulating liquid surrounding the' tube and incommunication with pressure chamber, said tube passing out through thetop of the vessel.

4. An electric switch of the fluid break type comprising a pressurechamber closed at its lower end and containing a fixed con tact, avessel surrounding and communicating with said chamber and adapted tocontain a supply of insulating liquid, a discharge tube extending upfrom the chamber and through the top of the vessel, and a contact rodarranged to extend through the tube to en "age the fixed contact.

5. A fluid break switch comprising coopcrating rod and socket contactmembers, an explosion chamber enclosing the socket contact member, adischarge tube extending upwardiy from said explosion chamber, aninsulating fluid in said tube and chamber, and a cap adapted to coverthe topof said tube when the switch is closed, said cap having a liquidseal with the tube to prevent evaporation of the insulating fluidtherein.

In witness whereof, I have hereunto set my hand this 31st da ofDecember, 1923. J O N D. HILLIARD.

